Olfactory sensitivity has been demonstrated to be important for directing a number of early behaviors in many mammalian species. While the role of chemosensitivity in behavioral development has been well studied, relatively little is known about the ontogeny of the principal relay in the olfactory system, the olfactory bulb. One purpose of the proposed research is to begin thorough anatomical, neurochemical and biochemical studies of bulb development in order to better understand maturation in this important sensory modality. A second purpose of the studies is to use the olfactory bulb to examine how experiential factors regulate brain development. While it has been demonstrated repeatedly that environmental input is important in shaping patterns of neural maturation, relatively little research has examined the cellular events through which the shaping occurs. The present grant is designed to pursue these issues by examining the effects of unilateral deprivation on the development of the olfactory bulb. Two specific problems will be addressed. First, the proposed studies will examine the sequence of postsynaptic events resulting from decreased airflow over the olfactory receptors. These studies will lead to an enhanced understanding of the mechanisms of experience-induced change. Second, the proposed studies will help to define which aspects of bulb development are experientially sensitive and which are independent in order to determine why experience has such important effects on neural growth at some stages in life and little at others. Quantitative neuroanatomical, neurochemical and biochemical techniques will also be used in these studies. The proposed experiments will help define normal and experientially modified growth in a primary sensory nucleus which has received relatively little attention. The findings will have important implications for our conceptions of early brain function, normal brain development and the cellular interactions through which environmental events control the patterning of brain growth.